A spectrum analyzer is an instrument for studying the spectrum structure of an electrical signal, and is a multi-function electronic measuring instrument that is used to measure parameters such as signal distortion, modulation degree, spectral purity, frequency stability and intermodulation distortion, and may be used to measure some parameters of a circuitry system such as an amplifier and a filter.
As shown in FIG. 1, there is a schematic block diagram of a spectrum analyzer in the prior art. The hardware of various parts generally included in a current spectrum analyzer will be described below.
Frequency of the spectrum analyzer typically ranges from kHz to GHz magnitude. By several down-conversions, usually, a radio frequency/microwave signal would be changed to a frequency which could be sampled by an ADC (Analog to Digital Converter). The functional circuit which can realize above operation is a radio frequency/microwave processing module.
The down-converted analog signal may be sampled by the ADC to achieve an analog-to-digital conversion. IQ data output by the ADC may be sent to a digital signal processing module for analysis and processing, and then a display module may convert the data to graph curves and display it on a screen.
An operator may operate the instrument by a panel menu. A Human-Computer Interaction module may transform these operations into control commands. A master control module may perform parameter setting and processing control for each functional circuit of the instrument, so as to complete a test and data processing required by the operator.
A clock and a power supply are two necessary hardware components in the instrument, mainly provide a clock and supply power for the interior circuits of the instrument.
During the implementation of the present application, the inventor has found at least the following problems in the prior art:
The existing spectrum analyzer has following disadvantages due to a single chassis design as a whole:    1. The frequency band supported by the instrument is fixed.    2. The measurement port supported by the instrument is fixed, and generally only one measurement port is supported.    3. Due to a relatively large volume and weight, it is not convenient for a test in a special circumstance (for example, equipment on a control tower, etc.).